The Jingnan campaign, or Jingnan rebellion, was a three-year civil war from 1399 to 1402 in the early years of the Ming dynasty of China. It occurred between two descendants of the Ming dynasty's founder Zhu Yuanzhang: his grandson Zhu Yunwen by his first son, and Zhu Yuanzhang's fourth son Zhu Di, Prince of Yan. Though Zhu Yunwen had been the chosen crown prince of Zhu Yuanzhang and been made emperor upon the death of his grandfather in 1398, friction began immediately after Yuanzhang's death. Zhu Yunwen began arresting Zhu Yuanzhang's other sons immediately, seeking to decrease their threat. But within a year open military conflict began, and the war continued until the forces of the Prince of Yan captured the imperial capital Nanjing. The fall of Nanjing was followed by the demise of Zhu Yunwen, the Jianwen Emperor and Zhu Di was thus crowned the Ming Dynasty's third emperor, the Yongle Emperor. Background In these Chinese names, the family name is Zhu. After establishing the Ming Dynasty in 1368, Zhu Yuanzhang (1328–1398), otherwise known as the Hongwu Emperor, began to consolidate the authority of the royal court. He assigned territories to the members of the royal family and stationed them across the empire. He had 26 sons, and of those who survived to adulthood, these princes were often assigned considerable land and forces. These members of the royal family did not have the administrative power over their territory, but they were entitled to a personal army that ranged from 3,000 to 19,000 men. Royal members that were stationed in the northern frontier were entitled to even larger forces. For instance, Zhu Yuanzhang's 17th son Zhu Quan, Prince of Ning, was said to have had an army of over 80,000 men. The original crown prince, Yuanzhang's first son Zhu Biao, died before Yuanzhang at the age of 36 in 1392. Instead of declaring another of his sons as crown prince, Yuanzhang then declared Biao's surviving eldest teenaged son Zhu Yunwen (1377–1402) as the new heir to the throne. Zhu Yunwen was thus the nephew of Yuanzhang's other sons the feudal princes and felt threatened by their military power. Prelude In May 1398, when his grandfather Zhu Yuanzhang died, Zhu Yunwen ascended to the throne and was named the Jianwen Emperor. He immediately issued an order that his uncles should remain in their respective territories, and then with the assistance of